The present invention is directed to a telephone network. More specifically, the present invention is directed to a telephone network that alters a speech signal during a telephone call.
In an ordinary telephone call between two callers, the speech signal received by a called party reproduces the original voice of a calling party, and vice versa. In order to enhance the reproduction, a network that transmits the telephone call typically performs speech processing on the speech signals. Examples of known speech processing done by networks on speech signals include automatic gain control, background noise suppression, echo cancellation and frequency equalization. Typically, the speech processing is automatically performed by the network during all telephone calls.
However, for various reasons, the calling party might desire that the called party hear an altered or distorted version of the calling party""s voice that is selectable by the calling party. For example, a calling party might want to disguise their voice so that the called party thinks that they are speaking to someone other than the calling party. Further, a calling party might want the called party to believe that the call is originating from a different location or environment than where the call is actually originating from. One example of this is a calling party calling from a land-based phone who wants the called party to believe that the call is originating from a cellular wireless phone. In this example, the calling party may want to pretend that the xe2x80x9ccellularxe2x80x9d signal has deteriorated and therefore have an excuse to hang up on the called party.
There are known devices that allow a calling party to disguise their voice. For example, with some devices a man""s voice can be altered so that it sounds like a woman""s voice, or a voice of another person. These known devices can be coupled to a calling party""s telephone so that the called party hears the altered voice.
However, there are disadvantages with using these known devices to alter the calling party""s voice. For one, they require the calling party to acquire the device and learn how to use it. Further, these devices typically alter the voice while it is in analog form. In most networks, however, a speech signal received from an analog telephone is first digitized, then delivered to one or more telephone switches, then converted back into analog form before being sent to the called party. This analog-to-digital (xe2x80x9cA/Dxe2x80x9d) and digital-to-analog (xe2x80x9cD/Axe2x80x9d) conversion can reduce the quality of the speech signal alteration, especially when the alteration is subtle as with the cellular phone example. Further, known digital speech processing techniques cannot be used to alter analog signals. These known techniques produce more accurate speech signal alterations than when analog speech is altered.
Moreover, even if the known devices first digitize the speech signal before altering it, the digitized speech signal must be converted back to analog before being sent to the network if the call is originating from a typical analog phone. Therefore, the speech signal is subject to even more A/D and D/A conversions, which results in a reduced quality of the alterations.
Further, if the calling party is involved in a multi-party call, the calling party may desire that their voice be altered differently for each called party, or that their voice be altered for one called party and not altered for another. This is not possible if the voice is altered at the calling party""s telephone.
Based on the foregoing, there is a need for a method and apparatus for altering a speech signal through speech processing that is selectable by the calling party, that does not require the calling party to obtain or use complicated voice alteration equipment, that processes a digitized speech signal while reducing the number of D/A and A/D conversions, and that enables the calling party""s voice to sound different to multiple called parties during multi-party calls.
One embodiment of the present invention is a network that establishes a telephone call between a calling party and a called party and alters speech signals generated by the calling party during the telephone call. The network includes a network node that is coupled to the transmit channel of the calling party and the receive channel of the called party.
The network node is programmed to receive a request to establish the telephone call from the calling party and receive a selection of a speech signal alteration from the calling party. The network node initiates the telephone call to the called party. Further, the network node alters the speech signal of the calling party based on the speech signal alteration selection.